Spark plug



c. G. CRAMER- SPARK PLUG Filed July 1, 1956 III I (YR/L G. (FAME/P,

Patented Feb. 16, 1937 UNITED STATES PATENT OFFICE SPARK PLUG Cyril G.Cramer, Binghamton, N. Y. Application July 1, 1936, Serial No. 88,457 2Claims. (01.123-169) My invention relates to spark plugs and mpreparticularly to a plug so constructed as to pro: duce a plurality ofsparks, and it consists in the constructions, arrangements andcombinations herein described and claimed.

It is an object of my invention to provide a spark plug in which thepositive electrode of the plug is formed as a series. of spark-gaps, aspark occurring at each of the gaps, thereby assuring" perfect ignitionof the fuel.

It is a. further object of the invention to provide a plug which may bereadily assembled and dismantled for cleaning. a

It is a still further object of the invention to provide a plug in whichthe plug shell, the insulater and the plug head are so formed interiorlyas to produce anignition chamber.

Additional objects, advantages and features of invention will beapparent from the following description considered in conjunction withthe accompanying drawing, wherein,

Figure 1 is a vertical sectional view of a plug constructed inaccordance with my invention.

Figure 2 is a cross section on the line 2- 2 of Fi ure 1.

Figure 3 is a plan view of an insulator employed in the plug. r g

In carrying out my invention I provide a metallic shell III having athreaded nipple II, atone end, for securement of the plug in an enginehead, as is customary. The upper portion of the shell is preferablyhexagonal in cross section,-for ready manipulation by the use of awrench.

The nipple I I includes a bore I2, the surface of "which is flaredoutwardly as at I3, and thence extended in a horizontal plane forming anannu-, lar seat I40 From the seat I4 the surface extends longitudinallyof the shell I0, as at I5, forming an annular well, being interiorlythreaded at its upper termination for reception of a packinggland I6.

Upon the seat of which stops flush with flared outer circumference ofwhich is slightly less the annular well. An annular, insulator I8 ispositioned upon the gasket I'I, anda similar gasket I9 is disposed uponthe upper face of the insu- I4, I provide a gasket I1, the bore wall I3,and the lator against which the gland I3 may engage.

The bores of the insulator and the last named gasket are the same as thegasket II so that a smooth uninterrupted surface is presented, and

. the gland I6 is undercut as at 20 and aligned with the bore of thegasket I 9. It willthus be seen that a chamber, generally indicated at2|, is provided which functions as a firing chamber.

than

. a suitable point is provided with a shoulder 23 is of slightly lesslength stroke of the pistons of tended inwardly of the forming a seatfor the enlarged portion 24 of an elongated insulator 25. Ascrew-threaded gland 26 is engaged. with the threads of the bore 22 formaintaining the insulator 25 in position, andpreferably packing rings 21are employed in conjunction with the enlargement 24, the shoulder 23 andgland 26, to effect a gas-tight connection.

The insulator 25 includes an electrode 28, the lower end of whichterminates approximately medially of the height of the insulator I8, fora purpose as will presently appear, and the upper end of the electrodeincludes a binding screw and nut 29 whereby connectionmay'-be made witha wire of an ignition system.

Referring now to Figures ing; particularly, the shell II] has a lug 30,ex-

annular'well I adapted to engage within a complemental notch 3| formedin the outer face of the insulator I8. The lug 30 than-the depth of thenotch 3|, thusstopping short of the inner wall 2 and 3 of the draw ofthe notch.

An electrode 32 is embedded in the insulator I8 extending axiallytherefromand stops short of the electrode 28' a necessary distance toform a' spark gap. The insulator I8 further includes; a series ofelectrodes 33, suitably spaced in annular formation, each of whichcomprises a right angularly disposed arm 34, extended in the directionof the next adjacent arm, but stopping short of contacting relationtherewith. Thus, it

will be apparent that a spark gap is formed between each arm '34 and thenext adjacent electrode. Any desired number of electrodes 33 may beincluded but the last electrode designated 33a. must be positioned so asto align medially of the notch 3|. This latter electrode must project ashort distance inwardly of the notch so as to readily contact the lug 30in order to complete the circuit'through the plug.

The operation The operation will be readily understood from thefollowing description, assuming that an engine is equipped with myplugs. The suction an engine will draw in the explosive mixture; thenext action occurring will be the compression of the charge in thecompression chamber of the engine, but compression of the gas alsooccurs in the chamber 2| of the plugs. .Thus there is a highly ignitiblemixture around the electrodes 28, 33 and 33a. When will occur betweeneach electrode, thereby producing a circular formation of fire which ishighly efiective upon the explosive mixture in the explosive space ofthe motor, consuming the mixture thoroughly, thereby causing the powerstroke. Then the exhaust stroke occurs, as customary, completing thecycle of the engine.

It will be apparent that with the use of my plug, the motor as well asthe plug itself will be kept free of carbon accumulations, due to theefi'icient and ample spark producing thorough burning of all combustiblefuel as well as residue which may be present. Also by providing a plugwith a series of sparks a quicker starting of a motor is made possibleas Well as efi'ecting economy in fuel consumption and obviously producesincreased power.

While I have shown and described a preferred form of the invention, thisis by way of illustration only, and I consider as my own all suchvariations in construction as fairly fall within the scope of theappended claims.

I claim:

1. A spark plug having a casing, an insulator ring therein, a gland forsecuring the ring in position, said casing ring and gland having aninterior structure defining a chamber, a positive electrode carried bythe gland, said electrode termiignition occurs, it will be apparent thata spark hating medially of the. chamber, a plurality of electrodesmounted in the insulator ring disposed axially therefrom and spaced withrespect to one another to define spark-gaps, one of said electrodesextending into close relation with the positive electrode to define aspark-gap, and one of said second named electrodes having contactingrelation with the casing.

2. A spark plug comprising a casing having a Well medially thereof, aninsulator ring seated in the well, a gland cooperable with the casingfor securing the ring in position, said casing and gland having portionsshaped for cooperation with the walls of the ring to define a chamber,

the periphery of said ring having an inwardly directed notch, a lug onthe interior of the casing and projecting into the notch, a positiveelectrode carried by the gland, said electrode terminating medially ofthe chamber, a plurality of electrodes mounted in the insulator ringdisposed axially therefrom, each electrode having a right angularportion stopping closely adjacent the next electrode to define a sparkgap, the first of said electrodes extending into close relation with thepositive electrode to define a spark gap, and the last of said secondnamed electrodes having contacting relation with the lug of the-casing.

CYRIL G. CRAMER.

